The greatest mathematician that never lived Pratik Aghor

When Nicolas Bourbaki applied
to the American Mathematical Society

in the 1950s,

he was already one of the most influential
mathematicians of his time.

He’d published articles
in international journals

and his textbooks were required reading.

Yet his application was firmly rejected
for one simple reason—

Nicolas Bourbaki did not exist.

Two decades earlier,
mathematics was in disarray.

Many established mathematicians had lost
their lives in the first World War,

and the field had become fragmented.

Different branches used disparate
methodology to pursue their own goals.

And the lack of a shared
mathematical language

made it difficult to share
or expand their work.

In 1934, a group of French mathematicians
were particularly fed up.

While studying at the prestigious
École normale supérieure,

they found the textbook
for their calculus class so disjointed

that they decided to write a better one.

The small group
quickly took on new members,

and as the project grew,
so did their ambition.

The result was
the “Éléments de mathématique,”

a treatise that sought to create
a consistent logical framework

unifying every branch of mathematics.

The text began
with a set of simple axioms—

laws and assumptions it would use
to build its argument.

From there, its authors derived
more and more complex theorems

that corresponded with work
being done across the field.

But to truly reveal common ground,

the group needed to identify
consistent rules

that applied to a wide range of problems.

To accomplish this, they gave new,
clear definitions

to some of the most important
mathematical objects,

including the function.

It’s reasonable to think of functions
as machines

that accept inputs and produce an output.

But if we think of functions
as bridges between two groups,

we can start to make claims about
the logical relationships between them.

For example, consider a group of numbers
and a group of letters.

We could define a function where
every numerical input corresponds

to the same alphabetical output,

but this doesn’t establish
a particularly interesting relationship.

Alternatively, we could define a function
where every numerical input

corresponds to a different
alphabetical output.

This second function sets up
a logical relationship

where performing a process on the input
has corresponding effects

on its mapped output.

The group began to define functions by how
they mapped elements across domains.

If a function’s output came
from a unique input,

they defined it as injective.

If every output can be mapped
onto at least one input,

the function was surjective.

And in bijective functions, each element
had perfect one to one correspondence.

This allowed mathematicians to establish
logic that could be translated

across the function’s domains
in both directions.

Their systematic approach
to abstract principles

was in stark contrast to the popular
belief that math was an intuitive science,

and an over-dependence on logic
constrained creativity.

But this rebellious band of scholars
gleefully ignored conventional wisdom.

They were revolutionizing the field,
and they wanted to mark the occasion

with their biggest stunt yet.

They decided to publish
“Éléments de mathématique”

and all their subsequent work
under a collective pseudonym:

Nicolas Bourbaki.

Over the next two decades, Bourbaki’s
publications became standard references.

And the group’s members took their prank
as seriously as their work.

Their invented mathematician claimed
to be a reclusive Russian genius

who would only meet
with his selected collaborators.

They sent telegrams in Bourbaki’s name,
announced his daughter’s wedding,

and publicly insulted anyone
who doubted his existence.

In 1968, when they could
no longer maintain the ruse,

the group ended their joke
the only way they could.

They printed Bourbaki’s obituary,
complete with mathematical puns.

Despite his apparent death, the group
bearing Bourbaki’s name lives on today.

Though he’s not associated
with any single major discovery,

Bourbaki’s influence informs
much current research.

And the modern emphasis on formal proofs
owes a great deal to his rigorous methods.

Nicolas Bourbaki may have been imaginary—
but his legacy is very real.

当 Nicolas Bourbaki 在 1950 年代
申请美国数学会

时,

他已经是他那个时代最有影响力的
数学家之一。

他在国际期刊上发表过文章

,他的教科书是必读的。

然而,他的申请被坚决拒绝
,原因很简单——

尼古拉斯·布尔巴基不存在。

二十年前,
数学处于混乱状态。

许多知名数学家
在第一次世界大战中丧生

,这个领域变得支离破碎。

不同的分支机构使用不同的
方法来追求自己的目标。

由于缺乏共享的
数学

语言,因此很难分享
或扩展他们的工作。

1934年,一群法国
数学家特别受够了。

在著名的
École normale supérieure 学习时,

他们发现
微积分课的教科书如此脱节

,于是他们决定写一本更好的教科书。

这个小组
很快就吸收了新成员

,随着项目的发展
,他们的野心也越来越大。

其结果
是“Éléments de mathématique”,这

是一篇旨在创建

统一数学各个分支的一致逻辑框架的论文。

本书
以一组简单的公理开始——

用于构建论证的定律和假设。

从那里,它的作者推导出
了越来越复杂的定理

,这些定理与
整个领域的工作相对应。

但要真正揭示共同点,

该小组需要

确定适用于广泛问题的一致规则。

为了做到这一点,他们

为一些最重要的
数学对象(

包括函数)给出了新的、清晰的定义。

将函数
视为

接受输入并产生输出的机器是合理的。

但是,如果我们将功能
视为两个群体之间的桥梁,

我们就可以开始对
它们之间的逻辑关系提出主张。

例如,考虑一组数字
和一组字母。

我们可以定义一个函数,其中
每个数字输入对应

于相同的字母输出,

但这并没有建立
一个特别有趣的关系。

或者,我们可以定义一个函数
,其中每个数字输入

对应一个不同的
字母输出。

第二个函数建立了
一种逻辑关系

,其中对输入执行处理对其映射的输出
有相应的影响

该小组开始
通过跨域映射元素的方式来定义功能。

如果一个函数的输出
来自一个唯一的输入,

他们将其定义为单射的。

如果每个输出都可以映射
到至少一个输入,则

该函数是满射的。

并且在双射函数中,每个元素
都具有完美的一一对应关系。

这使数学家能够建立
可以在两个方向上跨函数域进行转换的逻辑

他们
对抽象原理

的系统化方法与普遍
认为数学是一门直觉科学

以及对逻辑的过度依赖
限制了创造力的普遍看法形成了鲜明对比。

但是这群叛逆的学者
兴高采烈地忽视了传统智慧。

他们正在彻底改变这个领域
,他们想

用他们最大的特技来纪念这一时刻。

他们决定以集体笔名 Nicolas Bourbaki 出版
“Éléments de mathématique”

及其所有后续工作

在接下来的二十年里,布尔巴基的
出版物成为标准参考。

该小组的成员对他们的恶作剧
和他们的工作一样认真。

他们发明的数学家声称
自己是一位隐居的俄罗斯天才

,只会
与他选定的合作者见面。

他们以布尔巴基的名义发电报,
宣布他女儿的婚礼,

并公开侮辱
任何怀疑他存在的人。

1968 年,当他们
无法再维持这个诡计时

,这群人以他们
唯一能做的方式结束了他们的笑话。

他们打印了布尔巴基的讣告,
并附有数学双关语。

尽管他明显死亡,但以
布尔巴基的名字命名的团体今天仍然存在。

尽管布尔巴基
与任何一项重大发现都没有关联,但他

的影响为
当前的许多研究提供了信息。

现代对形式证明
的重视很大程度上归功于他严谨的方法。

Nicolas Bourbaki 可能是虚构的——
但他的遗产是非常真实的。